Abstract

In this investigation, natural radioactive contents in tiles manufactured in Nigeria and tiles imported
from China were measured using gamma ray spectroscopy. High Purity Germanium detector was
used to estimate the concentrations of some radioisotopes present in 17 samples of various tiles from
Nigeria and China. The average activity concentrations of 226Ra, 232Th, and 40K for the tiles were found
to be 68.2 ± 0.5; 173.9 ± 9.2 and 490 ± 15 Bq/kg and 58.2 ± 0.5, 161.5 ± 9.4 and 455.7 ± 15.1 Bq/kg for
the tiles from Nigeria and China respectively. Radiological hazard indices such as absorbed dose rate,
radium equivalent activity, external Hazard Index (Hex), internal Hazard Index (Hin), Annual Effective
Dose (mSv/y), Gamma activity Index (Iγ) and Alpha Index (Iα) were determined for both kind of tiles
from Nigeria and China. The mean values obtained were: 354.56 and 317.16 Bq/kg; 169.22 nGyh−1 and
153.92 nGyh−1; 0.95 and 0.87; 1.14 and 1.08; 1.59 mSv/y and 1.52 mSv/y; 1 and 1.15 and; 0.34 and
0.29 respectively. The mean value of radium equivalent obtained in this study is less than that of the
international reference value of 370 Bq/kg for the both kind of tiles.